Search results for "Ejecta"
showing 6 items of 76 documents
Supernova 1987A: a Template to Link Supernovae to their Remnants
2015
The emission of supernova remnants reflects the properties of both the progenitor supernovae and the surrounding environment. The complex morphology of the remnants, however, hampers the disentanglement of the two contributions. Here we aim at identifying the imprint of SN 1987A on the X-ray emission of its remnant and at constraining the structure of the environment surrounding the supernova. We performed high-resolution hydrodynamic simulations describing SN 1987A soon after the core-collapse and the following three-dimensional expansion of its remnant between days 1 and 15000 after the supernova. We demonstrated that the physical model reproducing the main observables of SN 1987A during …
High Angular Resolution ALMA Images of Dust and Molecules in the SN 1987A Ejecta
2019
We present high angular resolution (~80 mas) ALMA continuum images of the SN 1987A system, together with CO $J$=2 $\!\rightarrow\!$ 1, $J$=6 $\!\rightarrow\!$ 5, and SiO $J$=5 $\!\rightarrow\!$ 4 to $J$=7 $\!\rightarrow\!$ 6 images, which clearly resolve the ejecta (dust continuum and molecules) and ring (synchrotron continuum) components. Dust in the ejecta is asymmetric and clumpy, and overall the dust fills the spatial void seen in H$\alpha$ images, filling that region with material from heavier elements. The dust clumps generally fill the space where CO $J$=6 $\!\rightarrow\!$ 5 is fainter, tentatively indicating that these dust clumps and CO are locationally and chemically linked. In t…
Gas hazard assessment at the Monticchio crater lakes of Mt. Vulture, a volcano in Southern Italy
2009
Geochemical investigations have shown that there is a considerable inflow of gas into both crater lakes of Monticchio, Southern Italy. These lakes are located in two maars that formed 140 000 years ago during Mt. Vulture volcanos last eruptive activity. Isotopic analyses suggest that CO2 and helium are of magmatic origin; the latter displays 3 He ⁄ 4 He isotope ratios similar to those measured in olivines of the maar ejecta. In spite of the fact that the amount of dissolved gases in the water is less than that found in Lake Nyos (Cameroon), both the results obtained and the historical reports studied indicate that these crater lakes could be highly hazardous sites, even though they are loca…
Searching for differences in Swift's intermediate GRBs
2010
Gamma-ray bursts are usually classified through their high-energy emission into short-duration and long-duration bursts, which presumably reflect two different types of progenitors. However, it has been shown on statistical grounds that a third, intermediate population is needed in this classification scheme, although an extensive study of the properties of this class has so far not been done. The large amount of follow-up studies generated during the Swift era allows us to have a suficient sample to attempt a study of this third population through the properties of their prompt emission and their afterglows. Our study is focused on a sample of GRBs observed by Swift during its first four y…
On the formation of maars
1973
The Pleistocene maars in the Eifel region of Germany, and Massif Central in France, formed when fissures opened at the bottom of older valleys allowing stream water to pour down them and come into contact with rising magma. The resulting phreato-magmatic eruptions gave rise to both base surge and air-fall deposits. Spalling of wall rock at depth enlarged the fissure into an eruption chamber. Subsidence along a ring fault into the eruption chamber accounts for the larger crater cut into the country rocks. The volume relationship between the crater excavated, the ejected pyroclastic debris of the rim and the volume below the floor of the crater, indicates that the volume of the maar ejecta is…
Investigating the Structure of Vela X
2018
Vela X is the prototypical example of a pulsar wind nebula whose morphology and detailed structure have been affected by the interaction with the reverse shock of its host supernova remnant. The resulting complex of filamentary structure and mixed-in ejecta embedded in a nebula that is offset from the pulsar provides the best example we have of this middle-age state that characterizes a significant fraction of composite SNRs, and perhaps all of the large-diameter PWNe seen as TeV sources. Here we report on an XMM-Newton Large Project study of Vela X, supplemented by additional Chandra observations. Through broad spectral modeling as well as detailed spectral investigations of discrete emiss…